How much is the blockchain size reduction in zcash?


#1

My understanding is that since we do not store the entire transaction history, and only prove to each other we have the right to spend X ZECs, our blockchains are smaller.

How much smaller are they? Are they proportional to the number of addresses in use?


#2

Hi Edwin,
ZeroCash does store the entire transaction history just like Bitcoin. Also, because miners can not know the amount of currency at an address, it can not be pruned. So actually the block chain will likely be larger over time, ceterus paribus..


#3

Almost everything in our "JoinSplit" transactions (the confidential payment primitive of our system) can be pruned, with exception to the set of "nullifiers" which must be maintained somehow by every node. Nodes need to prevent two transactions from producing the same nullifier, as that would indicate a double-spend.

There are ways we'd like to explore minimizing the growth of this set, and reducing the maintenance cost by full nodes (perhaps by provably outsourcing maintenance of the set), but we aren't thinking about it right now.


#4

To be more precise, we have been thinking about it, but as a long-term consideration.